Machine substitutions for CrossFit, made simple

Every CrossFit class runs into it: the workout says run, but it's pouring rain, the rowers are taken, or a sore knee says no running today. This erg equivalency calculator is a CrossFit conversion chart that does the math for you. Pick the machine in the workout, enter the meters or calories, and it gives you the equivalent run, row, SkiErg, BikeErg and AirBike (Echo Bike or Assault Bike) numbers so your substitution keeps the same time and intensity.

How to use the erg equivalency calculator

1. Pick the machine in the workout: Running, AirBike, Rowing, SkiErg or BikeErg.
2. Enter the distance or calories. Running takes meters, kilometers or miles. Rowing, SkiErg and BikeErg take meters or calories. AirBike takes calories.
3. Read the equivalents. Each machine shows meters and calories plus about how long it should take. By default you'll see two numbers, men / women, the same way CrossFit workouts write "20/15 cal."
4. Turn on "Make my results more accurate" and enter your sex, bodyweight and fitness level to get one number made for you. For the most accurate result, switch "Personalize with" to Enter a time trial and enter one recent result: a mile run, a 10:00 max calorie AirBike, a 2k row, a 2k ski or 20:00 average watts on the BikeErg.

Quick CrossFit conversion chart

Here are the calculator's defaults for an intermediate athlete (men / women). They line up with the substitutions most gyms already use, like 400 m run = 500 m row = 1,000 m BikeErg = 20/15 cal on the bike.

Notice that meters barely change between men and women, while calories do. Calories track total power, which depends on body size. Meters track speed, which evens out more between athletes.

How the conversions are calculated

Most conversion charts are rules of thumb. This calculator uses exercise physiology so it can adjust to you. Equivalent pieces take about the same time at the same effort. For each machine, we estimate how fast or how much power you can hold, then convert that to the distance and calories each console would show.

1. Your engine. Each fitness level (Novice, Scaled, Intermediate, Rx, Elite) sets a typical VO2max (men 35, 42, 50, 57, 63; women 30, 36, 43, 50, 55 ml/kg/min). A time trial, if you enter one (mile run, 10:00 max calorie AirBike, 2k row, 2k ski or 20:00 BikeErg watts), sets it directly by working the model backward from your result. Workout effort runs from 95% of that for pieces up to 3 minutes down to 80% for an hour.
2. Running uses the ACSM running equation (VO2 = 0.2 × speed in m/min + 3.5) to turn effort into speed. Running speed depends on fitness, not size.
3. Machines turn your oxygen use (which grows with bodyweight) into watts with an equation for each one:
   • Rowing: from a study of elite rowers on the Concept2 (VO2 = 0.014 × watts + 0.34 L/min).
   • BikeErg: the ACSM cycling equation.
   • AirBike: a cycling-style equation with a little more oxygen per watt, because the arms work too.
   • SkiErg: you can only reach part of your full aerobic capacity on the ski (about 80–90% in studies) because the upper body does more of the work.
4. Console numbers come from the machines' own formulas. Concept2 pace = (2.80 ÷ watts)^1/3, Concept2 calories = 300 + 4 × watts ÷ 1.1639 per hour, and BikeErg distance is twice the rower's at the same watts. AirBike calories use the Assault AirBike's console formula (0.0404 × watts per minute).

Why bodyweight matters

Running is bodyweight-relative: a 200 lb athlete and a 130 lb athlete with the same fitness run about the same pace. On ergs, absolute power wins, so the bigger athlete covers more meters and burns more calories in the same time. In our model, a 400 m run at the same fitness equals about 420 m of rowing for a 130 lb athlete but 530 m for a 240 lb athlete. That's why a single chart never feels right for everyone in class.

Echo Bike vs. Assault Bike calories

Most gyms treat a calorie on the Rogue Echo Bike and the Assault AirBike as the same, and at the same cadence their consoles agree within about 5% (60 RPM is about 12.2 cal/min on the Echo and 11.6 on the Assault). So the calculator gives one AirBike number for both. If your gym also has a BikeErg, note it doesn't convert 1:1 with the air bikes.

Common substitutions CrossFit athletes search for

• Run to row conversion: a 400 m run is about 500 m on the rower for most athletes.
• Row to bike conversion: rowing meters roughly double on the BikeErg; 500 m row ≈ 1,000–1,050 m BikeErg.
• Assault Bike or Echo Bike to run: 20/15 calories is about a 400 m run.
• SkiErg to row conversion: most athletes ski about 5% fewer meters than they row in the same time.
• Calories to meters: on the Concept2 rower, 1 calorie is about 14–17 meters for most athletes at workout pace.
• 400 m run substitute, 800 m run substitute, 1 mile run substitute: see the chart above, or enter any distance in the calculator.

Tips for scaling cardio in a CrossFit workout

• Match the time, not the number. The goal of a substitution is the same stimulus. If the estimated time looks off for you, open the drawer and personalize it.
• Use your strongest data. A recent time trial beats a fitness-level guess. Use the test on the machine you're most practiced on, since skill on one machine doesn't always carry over.
• Skill counts. A former rower will beat these rowing numbers; someone new to the SkiErg will fall short. Adjust by feel after a few workouts.
• Very short sprints (under about 45 seconds) are mostly anaerobic, so equivalents there are rougher.

Frequently asked questions

What is 400 m running on the rower?

About 480–500 m for most athletes, or roughly 30–35 calories for men and 25–30 for women on a Concept2.

How many calories on the Assault Bike equal a 400 m run?

About 20 calories for men and 15 for women at an intermediate fitness level. Bigger athletes may need a few more.

How do I convert rowing to the BikeErg?

Double the meters as a starting point. At the same effort, the BikeErg covers about twice the rower's distance.

Are Echo Bike and Assault Bike calories the same?

Close enough for workouts. At the same cadence their consoles show calories within about 5% of each other, and most gyms count them 1:1.

Why are my numbers different from my gym's chart?

Gym charts assume an average athlete. Bodyweight and fitness change the conversion, especially for calories. Use the drawer to personalize your results.

Sources

1. American College of Sports Medicine metabolic equations (running and leg cycling), via the Woodway Curve console guide and ACSM's Guidelines for Exercise Testing and Prescription.
2. Prediction of oxygen uptake from power output on a Concept II ergometer in Danish elite rowers. Link
3. Validity and reliability of maximum oxygen uptake on an Air Bike arm- and leg-ergometer. Motricidade, 2022. Link
4. Comparison of peak aerobic capacity between the treadmill and a skiing ergometer. Journal of Exercise and Nutrition. Link
5. Upper-body peak VO2 on a ski ergometer vs. ski-striding (87% of full-body value). Link
6. Concept2 watts calculator and calorie formula. Watts, Calories
7. ZOAR Fitness Erg Calculator (Echo Bike and Assault AirBike console formulas). Link
8. Invictus cardio machine conversion chart (400 m run = 500 m row = 1,000 m BikeErg). Link
9. CrossFit CAP machine conversion chart. Link
10. WODprep: treating Echo, Assault and Airdyne calories the same. Link

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